Centaurea
centaurea, knapweed, star-thistle
Synonyms:
Cnicus [HC]
16 species
1 subspecies and varieties
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Centaurea benedictablessed thistle
Origin: Introduced
Centaurea calcitrapapurple starthistle, red starthistle
Origin: Introduced
Flowers: July - September
Centaurea cyanusbachelor's button, garden cornflower
Distribution: Widespread introductions in the Pacific Northwest
Habitat: Readily established when escaped from cultivation
Origin: Introduced from the Mediterranean region
Flowers: May - October
Centaurea diffusadiffuse knapweed, tumble knapweed, white knapweed
Distribution: Introduced throughout the Pacific Northwest; widespread and common in eastern Washington
Habitat: Noxious weed of dry, disturbed areas
Origin: Introduced from the eastern Mediterranean region
Flowers: July - September
Centaurea ×gerstlauerihybrid knapweed, meadow knapweed, protean knapweed
Distribution: Occurring on both sides of the Cascades in Washington; British Columbia to California, east to Idaho and Montana; also in eastern North America.
Habitat: Open ground, often where disturbed.
Origin: Introduced
Flowers: June-August
Centaurea ibericaIberian knapweed, Iberian starthistle
Origin: Introduced
Centaurea jaceabrown knapweed, brownray knapweed
Origin: Introduced from Europe
Flowers: July - October
Centaurea macrocephalaglobe knapweed
Distribution: Sparingly introduced in Washington
Habitat: Occasionally escapes from cultivation
Origin: Introduced
Flowers: June - September
Centaurea melitensisMaltese starthistle, tocalote
Distribution: Occurring chiefly west of the Cascades in Washington; British Columbia south to California and Mexicos, east to Texas and eastern North America.
Habitat: Roadsides and waste places.
Origin: Introduced from the Mediterranean region
Flowers: June-September
Centaurea montanamountain bluet, mountain cornflower, montane starthistle
Distribution: In scattered locations throughout Washington, but more common west of the Cascades; British Columbia to Oregon, east to Montana and Utah; in upper midwestern and northeastern U.S. and Canada.
Habitat: Occasionally escapes from cultivation; open, disturbed areas in shrub-steppe, forests, and along roadsides.
Origin: Introduced from Europe
Flowers: May-August
Centaurea nigrahardheads, black knapweed, lesser knapweed
Distribution: Introduced in the Pacific Northwest and northeastern United States
Habitat: Uncommon weed in disturbed soil
Origin: Introduced from Europe
Flowers: July - October
Centaurea nigrescensshort fringed knapweed, Tyrol knapweed
Distribution: Introduced and widely distributed in northeast United States and southeast Canada; occasional in the Pacific Northwest.
Habitat: Fields, roadsides and waste places.
Origin: Introduced from Europe
Flowers: July - October
Centaurea solstitialisyellow starthistle, St. Barnaby's thistle
Distribution: Introduced in most of the United States; chiefly east of the Cascades in Washington and Oregon
Habitat: Noxious weed of dry, disturbed areas
Origin: Introduced
Flowers: July - September
Centaurea stoebespotted knapweed
Distribution: Widely established throughout Washington; occurring throughout much of North America.
Habitat: Fields, roadasides, and waste areas.
Origin: Introduced
Flowers: June-October
ssp. australis – spotted knapweed
Centaurea trichocephalafeatherhead knapweed
Origin: Introduced
Centaurea ×varnensishybrid diffuse knapweed, sand knapweed
Origin: Introduced